muz'l (chacam; phimoo) : According to the Deuteronomic injunction (De 25:4), the ox was not to be muzzled while treading the grain, i.e. threshing. The muzzle was a guard placed on the mouth of the oxen to prevent them from biting or eating. The threshing ox would have ample opportunity of feeding (compare Ho 10:11). The Deuteronomic injunction is quite in accordance with the humane spirit which inspires it all through. Paul quotes this law in two places (1Co 9:9; 1Ti 5:18) to illustrate his view that the "laborer is worthy of his hire."
⇒See the definition of muzzle in the KJV Dictionary
T. Lewis